Updated September 03, 2013.

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Definition:

The facet joint capsule is an area of connective tissue that covers the facet joint from top to bottom. The connective tissue creates a sort of bulky seam that holds the two bones forming the facet joint together.

Each vertebra has four facet joints – two on the top (called superior facets) and two on the bottom (called inferior facets), so there are four facet joint capsules for each spinal bone.

The fibrous connective tissue of the capsule encases the whole joint, which contains synovial fluid. Synovial fluid is akin to WD-40 for the joint. It lubricates the facet joint and enables movement to occur.

The capsule of the facet joint is richly supplied with nerves -- which play a role in pain perception.

Pronunciation: fu-set

Also Known As: zygapophysis joint, zygapophyseal joint

Examples: The facet joint capsule covers the facet joint and plays a role in pain perception.